The present invention relates to a device for maintaining proper tension in flexible drive elements, such as chains or belts and the like, employed in machines or mechanisms of any kind for the purpose of transmitting a driving effort between drive and driven sprockets or pulleys and the like. More specifically, the present invention relates to a tensioning device which is particularly adapted for use with drives wherein the drive and driven members are of different diameters.
The present invention concerns a tensioning means intended for use with a flexible drive element in which each of the two runs or sides thereof is liable to be alternatively tensioned and relaxed, one run being tensioned and the other being slack during normal driving in one direction during acceleration, but said first-named run becoming slack and the other becoming tensioned in the event of overrun occurring in the mechanism or in the event of the drive being reversed.
Heretofore, it has been the practice in the art to provide tensioning means of the type described which either incorporated some sort of manually adjustable means, which required relatively frequent adjustment in order to compensate for wear in the drive components (see, for example, U.S. Pat. No. 3,060,760 granted to Minnis on 30 Oct. 1962), or incorporated a spring or other mechanical or hydraulic biasing means to maintain proper tension without manual adjustment (see, for example, U.S. Pat. No. 3,673,884 granted to Southiere on 4 July 1972). Of course, relatively frequent manual adjustment is bothersome and not desirable and a tensioning means incorporating biasing means are relatively complicated, somewhat unreliable due to spring failure and/or are relatively expensive.